let arr1: Array<number | string> = [1, '123', 2, 3, 54];
// let arr2: number[] = [1, 2, '', 3, 4, 2.1];

// 元组 : 约束了数组的类型  ip   string   number  string
// 约束 :
let tupe: [number, string, boolean];

tupe = [1, '', true];



